1. Field of the Invention
The present invention relates to a memory application tester, and more particularly, to a memory application tester wherein a motherboard is vertically mounted so as to increase a test throughput.
2. Description of the Related Art
Conventionally, an ATE (Automatic Test Equipment) is used for testing a semiconductor device by applying a certain signal pattern to the semiconductor device and analyzing a signal being output from the semiconductor device to determine a defect of the semiconductor device.
However, since the testing equipment such as the ATE is expensive, a price competitiveness is degraded due to high test cost. Moreover, since the test is carried out in a separate experimental environment rather than in an environment where the semiconductor device is actually installed and used, an accuracy of the test is degraded due to not embodying a property regarding various noises in the actual environment, resulting in an inaccurate determination of defect.
In order to overcome the above-described problems, in case of employing an application test wherein the semiconductor device is actually mounted in an electronic device under the environment where the semiconductor device is actually installed and used, i.e. an application environment is increasing. For example, when a test of a DRAM device used in a PC is carried out, the DRAM module is actually inserted in a motherboard of the PC and a test program according to the actual environment is executed to determine the defect depending on a result of the execution.
An example of the application testing equipment used for the PC is disclosed in Korean Patent Application No. 10-2002-0004428 titled “Semiconductor Memory Testing Equipment” filed on Jan. 25, 2002 by SiliconTech Incorporated. FIG. 1 is a diagram schematically illustrating a conventional memory application tester for testing a memory device packaged by a unit of a module.
As shown in FIG. 1, in accordance with the conventional application tester, a motherboard 110 for PC is horizontally mounted, a surface whereon a CPU 120, a memory controller 130 and a plurality of a memory sockets 140 are mounted faces a downward direction in order to prevent mechanical interference, and a reverse socket 150 (a type of memory socket) corresponding to one of the plurality of the memory sockets 140 is inversely inserted toward an upward direction. An interface board 160 wherein memory module 200 to be tested is mounted is mounted above the motherboard 110, and a handler (not shown) loads the memory module 200 to be inserted in a test socket 170. The test socket 170 is connected to the reverse socket 150 of the motherboard through a connector 180 so as to enable a signal exchange between the memory module 200 and the memory controller 130.
FIG. 2 is a diagram schematically illustrating a conventional memory application tester for testing a memory device by a unit of a component, wherein a test socket 170′ is configured to accommodate an individual component loaded by the handler contrary to FIG. 1 and other configuration are similar to FIG. 1.
As described above, in accordance with the conventional memory application tester, a separate interface board is mounted on the horizontally-mounted motherboard so that the memory device may be inserted in the socket by a unit of a module or a component. On the other hand, while a plurality of the motherboards should be mounted to increase a test throughput of the application tester per unit time, each of the motherboards excessively occupies an area horizontally in accordance with the horizontal arrangement structure, and a considerable time is required by the handler to load/unload the memory device.
In order to overcome these problems, the horizontally-mounted motherboards may be vertically stacked. However, a trace length between a motherboard at the bottom layer and the interface board may increase over an allowed limit, resulting in a degradation of reliability of the test result due to system defect. Therefore, in order for the memory application tester to operate properly, the trace length from the memory controller on the motherboard through the reverse socket to the test socket of the interface board and a signal integrity should be accurately maintained.